I have an array like:

    $array = array(&#39;foo&#39; =&gt; &#39;bar&#39;, 33 =&gt; &#39;bin&#39;, &#39;lorem&#39; =&gt; &#39;ipsum&#39;);
    echo native_function($array, 0); // bar
    echo native_function($array, 1); // bin
    echo native_function($array, 2); // ipsum

So, this native function would return a value based on a numeric index (second arg), ignoring assoc keys, looking for the real position in array.

Are there any native function to do that in PHP or should I write it?
Thanks


PHP - Get array value with a numeric index

What&#39;s the difference between the SQL datatype `NUMERIC` and `DECIMAL` ?
If databases treat these differently, I&#39;d like to know how for at least:

 - SQL Server
 - Oracle
 - Db/2
 - MySQL
 - PostgreSQL

Furthermore, are there any differences in how database drivers interpret these types?


Difference between DECIMAL and NUMERIC

I have new XmlDocument object, i.g. xml is created during my program...

I want all numeric values in created xml was with dot symbol instead of comma by default.

Can I do something to declare it once, not to parse every decimal value?

I.e. To set up this dot instead of comma somewhere in the beginning and don&#39;t worry about this till the end?

Set up dot instead of comma in numeric values

Recently I was going through an [old blog post by Eric Lippert](http://ericlippert.com/2008/05/23/precedence-vs-associativity-vs-order/ &quot;Click here to go to original post&quot;) 
in which, while writing about associativity he mentions that in C#, `(a + b) + c` is not equivalent to `a + (b + c)` for certain values of a, b, c. 

I am not able to figure out for **what types and range of arithmetic values** might that hold true and why.

Associativity math: (a + b) + c != a + (b + c)

Is it possible to set an element of an array to `NaN` in Python?

Additionally, is it possible to set a variable to +/- infinity? If so, is there any function to check whether a number is infinity or not?

Is it possible to set a number to NaN or infinity?

How would you check if a String was a number before parsing it?



How to check if a String is numeric in Java

I am creating a web page where I have an input text field in which I want to allow only numeric characters like (0,1,2,3,4,5...9) 0-9.

How can I do this using jQuery?


How to allow only numeric (0-9) in HTML  inputbox using jQuery?

I&#39;m unable to get numeric comparisons working:

&lt;!-- language: lang-sh --&gt;

    echo &quot;enter two numbers&quot;;
    read a b;

    echo &quot;a=$a&quot;;
    echo &quot;b=$b&quot;;

    if [ $a \&gt; $b ];
    then
        echo &quot;a is greater than b&quot;;
    else
        echo &quot;b is greater than a&quot;;
    fi;

The problem is that it compares the number from the first digit on, i.e., 9 is bigger than 10, but 1 is greater than 09.

How can I convert the numbers into a type to do a true comparison?




How can I compare numbers in Bash?

It seems that when I use a numeric type as a key name in an object, it always gets converted to a string. Is there anyway to actually get it to store as a numeric? The normal typecasting does not seem to work.

Example:

    var userId = 1;
    console.log( typeof userId ); // number
    myObject[userId] = &#39;a value&#39;;
    console.dir(myObject);

Dir Output:

    {
        &#39;1&#39;: &#39;a value&#39;
    }


What I **want** is this:

    {
        1: &#39;a value&#39;
    }


Advice?

Is there any way to use a numeric type as an object key?

Since this question gets asked about every week, this [FAQ][1] might help a lot of users.

 - How to convert an integer to a string in C++

 - how to convert a string into an integer in C++

 - how to convert a floating-point number to a string in C++

 - how to convert a string to a floating-point number in C++


  [1]: https://stackoverflow.com/tags/c++-faq/info
  

      

 


How to convert a number to string and vice versa in C++

In multiple browsers, the following code doesn&#39;t sort the numbers correctly:

    a = new Array();
    a.push(10);
    a.push(60);
    a.push(20);
    a.push(30);
    a.push(100);
    document.write(a.sort())

It returns `10,100,20,30,60`.

Anyone know why?

How to sort numbers correctly with Array.sort()?

Is there a function the .NET framework that can evaluate a numeric expression contained in a string and return the result? F.e.:

    string mystring = &quot;3*(2+4)&quot;;
    int result = EvaluateExpression(mystring);
    Console.Writeln(result); // Outputs 18

Is there a standard framework function that you can replace my `EvaluateExpression` method with?

Evaluating string &quot;3*(4+2)&quot; yield int 18

I want to preface this by saying I&#39;m an absolute programming beginner, so please excuse how basic this question is. 

I&#39;m trying to get a better understanding of &quot;atomic&quot; classes in R and maybe this goes for classes in programming in general. I understand the difference between a character, logical, and complex data classes, but I&#39;m struggling to find the fundamental difference between a numeric class and an integer class. 

Let&#39;s say I have a simple vector ` x &lt;- c(4, 5, 6, 6)` of integers, it would make sense for this to be an integer class. But when I do `class(x)` I get `[1] &quot;numeric&quot;`. Then if I convert this vector to an integer class `x &lt;- as.integer(x)`. It return the same exact list of numbers except the class is different. 

My question is why is this the case, and why the default class for a set of integers is a numeric class, and what are the advantages and or disadvantages of having an integer set as numeric instead of integer. 

What&#39;s the difference between integer class and numeric class in R

I wonder, how can I create a numeric zero-length vector in R?

How to create a numeric vector of zero length in R

Has anyone got an idea if there is any inbuilt functionality in Go for converting from any one of the numeric types to its binary number form.

For example, if `123` was the input, the string `&quot;1111011&quot;` would be the output.

Converting from an integer to its binary representation

I&#39;m trying to write an extension method on numeric types to be used in a fluent testing framework I&#39;m building. Basically, I want to do this:

    public static ShouldBeGreaterThan&lt;T&gt;(this T actual, T expected, string message)
        where T : int || T: double || etc...

Just `where T : struct` doesn&#39;t do, since that will also match `string` and `bool`, and possibly something else I&#39;m forgetting. is there something I can do to match only numeric types? (Specifically types that implement the `&gt;` and `&lt;` operators, so I can compare them... If this means I&#39;m matching dates as well, it doesn&#39;t really matter - the extension will still do what I expect.)

Generic constraint to match numeric types

I have an error being thrown by *SQL Server Management Studio* when running this code:

    declare @percentage numeric(3,2)
    set @percentage = cast(15 as numeric(3,2))

but when I change numeric declaration to 

    declare @percentage numeric(4,2)
    set @percentage = cast(15 as numeric(4,2))

everything goes fine.

Is there a limitation for numeric data type?


Why SQL Server throws Arithmetic overflow error converting int to data type numeric?

What is the best way of checking if input is numeric?

 - 1-
 - +111+
 - 5xf
 - 0xf

Those kind of numbers should not be valid. Only numbers like: 123, 012 (12), positive numbers should be valid.
This is mye current code:

    $num = (int) $val;
    if (
        preg_match(&#39;/^\d+$/&#39;, $num)
        &amp;&amp;
        strval(intval($num)) == strval($num)
        )
    {
        return true;
    }
    else
    {
        return false;
    }

PHP: Best way to check if input is a valid number?

I&#39;m hoping there&#39;s something in the same conceptual space as the old VB6 `IsNumeric()` function?

How can I check if a string is a valid number?

I need a regular expression for validation `two or one` numbers then `,` or `.` and again `two or one` numbers.

So, these are valid inputs:

    11,11  
    11.11  
    1.1  
    1,1  




How to validate numeric values which may contain dots or commas?

In angularjs is there any functionality available that allows only numbers to be typed into a text box [like][1]


  [1]: http://www.texotela.co.uk/code/jquery/numeric/

angularjs: allows only numbers to be typed into a text box

I have a data frame taken from a .csv-file which contains numeric and character values. I want to convert this data frame into a matrix. All containing information is numbers (the non-number-rows I deleted), so it should be possible to convert the data frame into a numeric matrix. However, I do get a character matrix.

I found the only way to solve this is to use `as.numeric` for each and every row, but this is quite time-consuming. I am quite sure there is a way to do this with some kind of `if(i in 1:n)`-form, but I cannot figure out how it might work. Or is the only way really to already start with numeric values, like proposed here(https://stackoverflow.com/questions/8052828/making-matrix-numeric-and-name-orders)?

Probably this is a very easy thing for most of you :P

The matrix is a lot bigger, this is only the first few rows... Here&#39;s the code: 

    cbind(
    as.numeric(SFI.Matrix[ ,1]),
    as.numeric(SFI.Matrix[ ,2]),
    as.numeric(SFI.Matrix[ ,3]),
    as.numeric(SFI.Matrix[ ,4]),
    as.numeric(SFI.Matrix[ ,5]),
    as.numeric(SFI.Matrix[ ,6]))  
    
    # to get something like this again:

    Social.Assistance Danger.Poverty GINI S80S20 Low.Edu        Unemployment 
    0.147             0.125          0.34    5.5   0.149        0.135 0.18683691
    0.258             0.229          0.27    3.8   0.211        0.175 0.22329362
    0.207             0.119          0.22    3.1   0.139        0.163 0.07170422
    0.219             0.166          0.25    3.6   0.114        0.163 0.03638525
    0.278             0.218          0.29    4.1   0.270        0.198 0.27407825
    0.288             0.204          0.26    3.6   0.303        0.211 0.22372633



Thank you for any help!

All Numeric Solutions on Gang of Coders

Total of 22 Numeric Solutions